The field of the present invention is front suspension systems for motorcycles.
Motorcycles have been devised which incorporate a front suspension mechanism using a front swing arm instead of a conventional front fork suspension mechanism. One such motorcycle is illustrated in Japanese Patent Publication No. 58-49435, U.S. Pat. No. 4,265,329. In such prior swing arm front suspension motorcycles, a connecting plate has typically been fixed to either sidewall of the engine which is located at the center of the motorcycle body. The swing arm of such a vehicle is typically connected to the connecting plate at the proximal end thereof and to a steering plate at the distal end thereof. The steering plate rotatably supports a front wheel. A cushion unit typically extends between the swing arm and the connecting plate affixed to the engine. Such a system is specifically illustrated in the aforementioned patent.
Difficulties have been encountered with such arrangements. With the cushion member fixed at one end to the swing arm, the swing arm is proportional to the stroke of the cushion unit. This results in a relatively rough ride on adverse road conditions.
One of the specific advantages of the structural architecture of such motorcycles employing a front swing arm is a reduction in overall weight. However, the mounting of the cushion member to frame members associated with the power unit requires substantial strength for the supporting frame member or connecting plate. As a result, such mounting plates are typically quite heavy, detracting from the overall weight advantage of such motorcycle designs.